Collections of active particles serve as examples for far-from-equilibrium systems, and a considerable amount of research was devoted to finding out which thermodynamic concepts can be used to describe them [1]}, [2]}, [3]}, [4]}. Among the remarkable properties of active particles are new emergent phenomena [5]}, [6]}, [7]}, [8]}, [9]}, motility induced phase separation [10]}, [11]}, [9]}, and flocking at large numbers [13]}, [14]}. As a result, giant number fluctuations were observed in many active systems [15]}, [16]}, [17]}, [18]}.
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